PROTON MAGNETIC resonance (MR) spectroscopy may provide a way to study early central nervous system effects of human immunodeficiency virus (HIV) infection. Results of a preliminary study reported at the 78th Scientific Assembly and Annual Meeting of the Radiological Society of North America, held in Chicago, Ill, suggest that MR spectroscopy may be able to detect biochemical changes in brains of HIV-infected individuals who have no symptoms of the acquired immunodeficiency syndrome (AIDS) or evidence of neurocognitive dysfunction. "Proton MR spectroscopy, which can be integrated easily with conventional magnetic resonance imaging devices, provides a means of measuring the levels of various biochemicals in the brain completely noninvasively," says Robert E. Lenkinski, PhD, associate professor of radiology, University of Pennsylvania School of Medicine, Philadelphia, the principal investigator of the study. <h3>Biochemical Fingerprints</h3> In essence, the magnetic resonance spectral patterns obtained are "a collection of fingerprints of the various biochemical compounds present